Biogenic silver nanoparticles (bio-Ag 0) decrease biofouling of bio-Ag 0/PES nanocomposite membranes.

Biofouling is a major problem for the application of membrane technology in water and wastewater treatment. One of the practical strategies to decrease biofouling is the use of advanced anti-biofouling membrane material. In this study, different amounts of biogenic silver nanoparticles (bio-Ag(0)) were embedded in polyethersulfone (PES) membranes, using the phase-inversion method. The effects of the bio-Ag(0) content on the structure of the membrane and its filtration performance were systematically investigated. The results demonstrated that silver-containing nanostructures were uniformly distributed on membrane surface. Bio-Ag(0) incorporation slightly increased the hydrophilicity of the PES membrane and increased the permeate flux. The anti-bacterial and anti-biofouling properties of the bio-Ag(0)/PES nanocomposites membrane were tested with pure cultures (Escherichia coli and Pseudomonas aeruginosa) and a mixed culture (an activated sludge bioreactor), respectively. The bio-Ag(0)/PES composite membranes, even with the lowest content of biogenic silver (140 mg bio-Ag(0)m(-2)), not only exhibited excellent anti-bacterial activity, but also prevented bacterial attachment to the membrane surface and decreased the biofilm formation during a 9 weeks test.